Digital Video Broadcasting (DVB) systems distribute data using a variety of approaches, including by satellite (DVB-S, DVB-S2 and DVB-SH), DVB-SMATV for distribution via SMATV), cable (DVB-C), terrestrial television (DVB-T), second generation digital terrestrial television (DVB-T2), and digital terrestrial television for handhelds (DVB-H, DVB-SH). Digital Video Broadcasting (DVB) is a suite of internationally accepted open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium with more than 270 members, and are published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC) and European Broadcasting Union (EBU). The associated standards define the physical layer and data link layer of a distribution system. Devices interact typically with the physical layer through a synchronous parallel interface (SPI), synchronous serial interface (SSI), or asynchronous serial interface (ASI). Data is typically transmitted in MPEG-2 transport streams with some additional constraints (DVB-MPEG).
The distribution systems for the different DVB standards differ in the modulation schemes and error correcting codes used, due to the different technical constraints. For example, DVB-S Super High Frequency (SHF) uses quadrature phase shift keying (QPSK), 8PSK or 16-quadrature amplitude modulation (QAM). DVB-S2 uses QPSK, 8PSK, 16 amplitude and phase shift keying (APSK) or 32APSK. QPSK and 8PSK are the only versions regularly used. DVB-C (VHF/UHF) uses QAM: 16-QAM, 32-QAM, 64-QAM, 128-QAM or 256-QAM. DVB-T (VHF/UHF) uses 16-QAM or 64-QAM (or QPSK) in combination with Coded Orthogonal Frequency Division Multiplexing (COFDM) and can support hierarchical modulation.